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Brakes don't work in cold weather

Hello Everyone!

Thank you for any help you can offer! I have a 2000 Nissan Altima that works great except when the weather becomes cold in the winter. The brakes don’t work when I turn on my car. The brake lever will not press down at all and once or twice (before I realized this was happening) my car went sliding down the road without an ability to stop. I can’t tell if they start working after the car warms up or after I’ve pumped them for a while because they’ll start working again at random times. Sometimes it takes a few seconds and sometimes it takes a few minutes. Thank you for any advice! Have a wonderful day!

Allie

Sounds like a bad brake booster or maybe the vacuum line to it is leaking. Not sure why it would be more prevalent in cold weather to the point you are describing, though.
If you are physically not able to press the pedal down without having power assist, is a very dangerous condition so please get it taken care of soon.

Does your engine start and run smoothly in cold weather? Do you live at high altitude?

Good question. I see where you’re going with that, Caddy. That could very well point to a vacuum problem.

I think the engine runs smoothly it is only the brakes. I live at ~8,500’ elevation and work at ~10,000’ elevation. I’ve looked it up online before and it seems to be a common problem with Altimas in cold weather.

Like RemcoW said, I think the problem is that there is no power assist to your brakes. You should be able to press the brake pedal to get the car to stop, but it may require much more power–maybe even both feet depending how big and strong you are. Try pushing on the pedal really hard and see if it moves next cold morning. If so, you have a problem with the power booster or vacuum system to the booster. Whatever the case, if you are unable to safely brake the car, have it towed to a shop. Don’t drive it and risk damaging the car, you, or someone else.

Does cold weather mean below freezing? Does this happen when the air temperature is above freezing? If it only happens below freezing, then I suspect that you have water in the booster or in the vacuum check valve to the booster.

Automotive engines operating at those altitudes produce greatly reduced manifold vacuum especially at cold start-up…At those elevations, early morning temperatures are much lower than most of us experience. I suspect your power-brake booster, a vacuum operated device, was never tested to operate at 10 below zero and 8500’ elevation. Other than a heated garage, this could be a tricky problem to solve…

Why isn’t the car in the hands of a brake specialist as we speak. You can’t stop and you’re getting our opinion from afar ? Just asking. Don’t drive it again and have it trailered or towed.

I’m assuming all the wheels have been pulled and the brake components given a visual inspection, are within specs, and that the brake fluid is ok. If so, I expect it as the others say, this is a defective brake booster. This should be easy and relatively inexpensive to fix.

The only other thing I can think of is a problem with the ABS system, if the car has one.

If the temperature is near freezing and the humidity is relatively high ice may be accumulating at the vacuum booster vent or check valve.

If cold means below freezing, than you have classic symptoms of moisture in your brake fluid. It forms an ice block.
You need to have the system completely flushed out with fresh fluid. Any competant shop can do this.

I’ve had it happen to me before…I had water in the line that turned to ice. I learned the hard way that you should change your fluid every now and then.

I want to second what mountainbike and Mike stated, as the symptoms could indeed be the result of brake fluid that has never been changed.

And, there is an additional possibility–namely the seals in the master cylinder.

Back around 1997, Subaru recalled a number of cars that had been equipped with master cylinders whose piston seals shrank just enough in frigid conditions so that there was insufficient fluid pressure when braking. If Subaru’s supplier made this mistake, it is possible that Nissan’s supplier might have made a similar mistake with the master cylinder for your model.

So–in addition to having the brake fluid flushed, I would suggest checking with a Nissan dealer in order to find out if there was ever a recall on your car for defective master cylinder piston seals.

In any event, this situation is something that requires immediate attention.

Thank you everyone! For those of you that are inquiring - I’m using my car now because it is not below freezing yet. Also, I cannot leave it in my garage to keep warm because my driveway becomes an icy slip-n-slide.

I really appreciate all of your advice. I will bring the car to a mechanic to look at the brake booster as you all have advised, get the brake fluid flushed, and have the seals checked with the master cylinder. If any of that didn’t make sense sorry - I’m mechanically ignorant. Once I figure out what caused the problem I’ll post another comment so that you can have some closure.

I don’t have any other way to thank you guys for all of your help except to offer answers to any geology questions you might have (I know, nerdy).

Again, thank you.

Your follow up post is all the thanks I need. Being able to help someone and having them appreciate it is worth its weight in gold.

Sincere best.